This relates generally to imaging systems, and more particularly to package structures for image sensors.
Electronic devices such as cellular telephones, cameras, and computers often include imaging systems that include digital image sensors for capturing images. Image sensors may be formed having a two-dimensional array of image pixels that convert incident photons (light) into electrical signals. Electronic devices often include displays for displaying captured image data.
Image sensors formed on a die are often packaged to enable an imaging system to easily incorporate an image sensor into its design and architecture. In conventional package structures for image sensors, an image sensor die is bonded to a package substrate using discrete mounts. Bonding the image sensor to a package substrate using discrete mounts is known as flip-chip bonding.
After bonding the image sensor to a package substrate using flip-chip bonding, an electrically insulating adhesive is deposited in between the gaps between the discreet mounts, in a process known as underfilling. Adhesives used in an underfilling process may be referred to as underfill adhesives. Underfill adhesives may be used to redistribute stress away from solder joints, and prolong the thermal aging of solder joints of the discrete mounts.
In conventional image sensor packaging, image pixel arrays of an image sensor are susceptible to damage or contamination by underfill adhesives applied during the packaging process, as well as damage or contamination by environmental particles or particles from a mounting substrate. Additionally, conventional image sensor packaging often lacks sufficient rigidity for certain operating conditions. Furthermore, it is difficult to adjust the alignment of various structures in conventional image sensor packages during manufacture.
Therefore, it would be desirable to provide improved image sensor packaging.